Myocardial Flow Reserve by MRI: Myocardial perfusion distribution and myocardial blood flow reserve can be simultaneously assessed using a MRI first-pass Gd contrast injection approach. Rapid MR imaging (MRI) during the first pass injection of Gd compounds is used to assess myocardial perfusion with a spatial resolution of 2-3 mm, and to detect any regional impairments of myocardial blood flow (MBF) that may lead to ischemia. The myocardial perfusion reserve (MPR) is a useful concept for quantifying the vasodilator response. The perfusion reserve can be estimated from the ratio of MBFs during vasodilation and at baseline, similar to that described by labeled microspheres. Assessment of myocardial blood flow and flow reserve by cardiac MR is a robust technique. There is a relationship between CAC and hyperemic flow reserve, although it may be more or less strong depending upon the methodology employed. However, CAC is still a marker of the atherosclerotic process and this process appears to be more aggressive in T1D. The investigation of MBF reserve as a marker of early or more aggressive vasculopathy is important, especially in a disease with significant morbidity and mortality from cardiovascular events.